Proteins from vegetable seeds are interesting for research at present because they are an\ud abundant alternative to animal-based sources of proteins and petroleum-derived polymers.\ud They are a renewable and biodegradable raw material with interesting functional and/or\ud physico-chemical properties. In microencapsulation, these biopolymers are used as a wall\ud forming material for a variety of active compounds. In most cases, two techniques of\ud microencapsulation, spray-drying and coacervation, are used for the preparation of\ud microparticles from vegetable proteins. Proteins extracted from soy bean, pea and wheat have\ud already been studied as carrier materials for microparticles. These proteins could be suitable\ud shell or matrix materials and show good process efficiency. Some other plant proteins, such as\ud rice, oat or sunflower, with interesting functional properties could be investigated as potential\ud matrices for microencapsulation

Enzymatic and chemical modifications of soy protein isolate (SPI) were studied in order to\ud improve SPI properties for their use as wall material for a-tocopherol microencapsulation by\ud spray-drying. The structural modifications of SPI by enzymatic hydrolysis and/or N-acylation\ud were carried out in aqueous media without any use of organic solvent neither surfactant.\ud Emulsions from aqueous solutions of native or modified SPI and hydrophobic a-tocopherol,\ud were prepared and spray-dried to produce a-tocopherol microparticles. The effect of protein\ud modifications and the influence of the core/shell ratio on both emulsions and microparticles\ud properties were characterised. The obtained results demonstrated that oil-in-water emulsions\ud prepared with modified proteins had lower droplet size (0.5-0.9 μm) and viscosity (3.6-14.8\ud mPa×s) compared to those prepared with native proteins (1.1 μm and 15.0 mPa×s respectively).\ud Efficiency of oil retention decreased after protein hydrolysis from 79.7 to 38.9%, but the\ud grafting of hydrophobic chain by acylation improved efficiency of a-tocopherol retention up\ud to 94.8%. Moreover, higher emulsion viscosity, particle size and process efficiency were\ud observed with the increase of a-tocopherol amount